Geophysical Constraints on the Crustal Architecture of the Transtensional Warm Springs Valley Fault Zone, Northern Walker Lane, Western Nevada, USA

Abstract

Fault reactivation occurs when preexisting faults slip in a sense different than their original kinematics. A common mode of fault reactivation is basin inversion (Cooper et al., 1989; in which former normal faults become reverse and thrust faults. Notable examples of basin inversion include the Uinta Mountains in North America (Stone, 1993), the Atlas Mountains in northern Africa (Lowell, 1995), and the Northern Apennines in Europe (Scisciani et al., 2001).Despite the relatively widespread recognition of normal faults reactivated as reverse faults in Earth's continental crust, relatively little is known about the seismogenic behavior of normal fault systems overprinted by active strike-slip deformation. Detailed three-dimensional seismic studies in the North Sea show that preexisting normal faults can be reactivated in a wide variety of slip senses when overprinted by shear and transtension (T. B. Phillips et al., 2018). Structural studies of long-dead normal fault systems reactivated as strike-slip faults document structural, rather than seismogenic, characteristics such as how normal fault relay zones appear to control basin geometry and fluid flow even after reactivation in strike slip (Barton et al., 1998; Rotevatn & Peacock, 2018). Analog laboratory models demonstrate that preexisting normal faults strongly influence the pattern of subsequent strike-slip faulting (Richard & Krantz, 1991), but the